Screw having a sealing washer assembly

ABSTRACT

A screw including a sealing washer assembly and a shank which defines a screw axis and has a thread in at least a portion thereof and whose one end is provided with a head. The sealing washer assembly is disposed on the shank and includes at least one sealing washer and a reinforcing washer, said reinforcing washer having a thickness, and the sealing washer assembly having a cumulative thickness is disclosed. The sealing washer assembly is spaced, along the screw axis, at a distance from an underside of the head facing the shank, said distance being greater than the thickness of the reinforcing washer and smaller than the cumulative thickness of the sealing washer assembly.

This claims priority to German Patent Application DE 10 2008 041 411.5,filed Aug. 21, 2008, the entire disclosure of which is herebyincorporated by reference herein.

The present invention relates to a screw having a sealing washerassembly and a shank which defines a screw axis and has a thread in atleast a portion thereof, and whose one end is provided with a head; thesealing washer assembly being disposed on the shank and including atleast one sealing washer and a reinforcing washer, said reinforcingwasher having a thickness, and the sealing washer assembly having acumulative thickness. Screws of this type may be in the form ofself-tapping screws or self-drilling screws and are used, for example,for screwing together metal sheets, the screw joint being protected fromingress of liquid by a sealing washer assembly.

BACKGROUND OF THE INVENTION

In U.S. Pat. No. 3,500,712, there is disclosed a screw of this typehaving a head of hexagonal peripheral geometry as a torque-receivingmeans and a shank having a peripheral thread. The shank end facing thehead has an unthreaded region onto which is fitted a washer assembly.The washer assembly includes a sealing washer made of an elasticmaterial and a relatively rigid washer made, for example, of metal. Thewasher assembly is relatively close to, or directly contiguous to theunderside of the screw head.

SUMMARY OF THE INVENTION

This screw has the disadvantage of not being suited for being magazinedon a magazine having, for example, a receiving channel for screw heads.

It is an object of the present invention to overcome the above-mentioneddisadvantages and to devise a screw that is capable of being readilymagazined.

The present invention, provides spacing a sealing washer assembly, alongthe screw axis, at a distance from an underside of the head facing theshank, said distance being greater than the thickness of the reinforcingwasher and smaller than the cumulative thickness of the sealing washerassembly. This enables the screw to be readily magazined on an elongatedmagazine that has a receiving channel and whose wall thicknesscorresponds to the thickness of the reinforcing washer at a maximumdeviation of +/−20% therefrom. In the region of the opening of themagazine, the magazine walls extend into the space between the head andthe sealing washer assembly of the screw so as to hold the screw on themagazine.

The end of the shank facing the head may be advantageously provided witha cylindrical collar whose end facing away from the head has areinforcing washer fitted thereon and whose length along the screw axiscorresponds to the distance plus the thickness of the reinforcingwasher. Thus, the distance between the underside of the head and thesealing washer assembly is determined by the collar, thereby allowingfor easy assembly of the screw together with the sealing washerassembly. In addition, the provision of a collar is beneficial from aproduction engineering standpoint.

It is also advantageous if, in the region of the collar, the shank has afirst diameter which is greater than a second diameter of the shank inthe region of the thread. This enables the collar to serve as a stopwhen the screw is driven into a substrate, thereby preventing thesealing washer from being damaged or squeezed out in the process.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described with reference to an exemplaryembodiment illustrated in the drawing, in which:

FIG. 1 is a side view of an inventive screw having a sealing washerassembly;

FIG. 2 is a view showing the inventive screw and sealing washer assemblyof FIG. 1 on a magazine strip;

FIG. 3 is a view showing the screw and sealing washer assembly of thepresent invention screwed into a workpiece.

DETAILED DESCRIPTION

The inventive screw 10 and its sealing washer assembly 20 shown in FIGS.1 and 2 has a shank 12, a portion of which is provided with a thread 15,and whose one end has a tip (not shown in the figures), while its other,opposite end is provided with a head 11. The tip may be designed as adrilling tip or as a pointed tip. Screw axis S defines an axialdirection of screw 10. Head 11 features a torque-receiving means 17 fora screw tool, which has an exterior polygonal portion, in particular anexterior hexagonal portion, adapted to be engaged by a wrench.

The end of shank 12 facing head 11 is provided with a cylindrical collar13. The axial end of collar 13 facing away from head 11 has a stopsurface 14. In the region of collar 13, shank 12 has a first diameter D1which is greater than a second diameter D2 of shank 12 in the region ofthread 15 (see in particular FIG. 1).

Sealing washer assembly 20 includes a sealing washer 21 and, contiguoustherewith, a reinforcing washer 22 made of a rigid material such asmetal, in particular steel. Reinforcing washer 22 has a thickness U, andsealing washer assembly 20 has a cumulative thickness G (see inparticular FIG. 1). Sealing washer assembly 20 is spaced from head 11along screw axis S such that there is a distance A between an upper side24 of reinforcing washer 22 of said sealing washer assembly and anunderside 16 of said head facing shank 12. Distance A is greater thanthickness U of reinforcing washer 22 and smaller than cumulativethickness G of sealing washer assembly 20 (see in particular FIG. 1).When screw 10 is in its initial position, reinforcing washer 22 isdisposed on the end of collar 13 facing away from head 11, while sealingwasher 21 abuts stop surface 14 of collar 13. To this end, seconddiameter D2 of shank 12 in the region of collar 13 is slightly smallerthan the diameter of the opening of reinforcing washer 22. A length L ofcollar 13 along screw axis S corresponds to distance A plus thickness Uof reinforcing washer 22.

In FIG. 2, screw 10 is placed on a magazine 30 having a receivingchannel 31 for the heads 11 of a plurality of screws 10 and a slottedopening 32 for the shanks 12 of screws 10. Furthermore, magazine 30 has,at least in the region adjacent to slotted opening 32, a wall thicknessM which is smaller than distance A between underside 16 of head 11 andsealing washer assembly 20. Wall thickness M preferably corresponds tothickness U of reinforcing washer 22 at a maximum deviation of +/−20%therefrom. Distance A between sealing washer assembly 20 and underside16 of head 11 facing shank 12 allows screw 10 to be guided with ease ofmotion on magazine 30; even given a screw axis S that is slightlyoblique relative to the longitudinal axis of magazine 30, it is stillmovable within receiving channel 31.

FIG. 3 shows screw 10 screwed into a workpiece 40, with a flat member41, such as a sheet of metal, having been fixed thereto. During theprocess of screwing screw 10 into workpiece 40, distance A betweenunderside 16 of head 11 and sealing washer assembly 20 was reduced tozero, and sealing washer assembly 20 was slipped completely onto collar13. In this condition, sealing washer 21 abuts sealingly on flat member41.

What is claimed is:
 1. A screw comprising: a sealing washer assembly; ashank defining a screw axis and having a thread in at least a portionthereof and having a first end; and a head at the first end and havingan underside facing the shank; the sealing washer assembly beingdisposed on the shank and including at least one sealing washer and areinforcing washer, the reinforcing washer having a thickness, and thesealing washer assembly having a cumulative thickness, the sealingwasher assembly being spaced, along the screw axis, at a distance fromthe underside, the distance being greater than the thickness of thereinforcing washer and smaller than the cumulative thickness of thesealing washer assembly; wherein the first end of the shank is providedwith a cylindrical collar whose end facing away from the head has thereinforcing washer fitted thereon, the collar having a length along thescrew axis corresponding to the distance plus the thickness of thereinforcing washer; wherein in the region of the collar, the shank has afirst diameter which is greater than a second diameter of the shank inthe region of the thread.
 2. A magazine for a fastening tool, comprisinga receiving channel having a wall, the wall having a wall thickness, ascrew comprising a sealing washer assembly and a shank defining a screwaxis and having a thread in at least a portion thereof, the shank havinga first end provided with a head; the sealing washer assembly beingdisposed on the shank and including at least one sealing washer and areinforcing washer, the reinforcing washer having a thickness, and thesealing washer assembly having a cumulative thickness, the sealingwasher assembly being spaced, along the screw axis, at a distance froman underside of the head facing the shank, the distance being greaterthan the wall thickness, the head being received in the receivingchannel, and the wall engaging between the underside of the head facingthe shank and the reinforcing washer; and wherein the first end of theshank is provided with a cylindrical collar whose end facing away fromthe head has the reinforcing washer fitted thereon and whose lengthalong the screw axis corresponds to the distance plus the thickness ofthe reinforcing washer; wherein in the region of the collar, the shankhas a first diameter greater than a second diameter of the shank in theregion of the thread.
 3. The magazine as recited in claim 2 wherein thedistance is greater than the thickness of the reinforcing washer.
 4. Themagazine as recited in claim 3 wherein the distance is smaller than thecumulative thickness of the sealing washer assembly.
 5. The magazine asrecited in claim 2 wherein the distance is smaller than the cumulativethickness of the sealing washer assembly.